The activities of tissue- type plasminogen activator (t-PA) and plasminogen activator inhibitor(PAl) in plasm from 61 patients with retinal vein occlusion (RVO) were measured by using chromatogenous substrate s-2390 assay.The results showed that the t-PA activity in the patients with RVO were decreased (1.69plusmn;0. 56IU/ml, P＜0.01) and PAI activity increased (8.80plusmn;1.60AU/ml, P＜0. 01) comparing with health subjects 2.07plusmn;0.40IU/ml and 7.33plusmn;0.67AU/ml respectively. Among the patients, t-PA activity in the patients with ischemic retinopathy was more obviously decreased (1.35plusmn;0.43IU/ml, P＜0.01) and the activity of PAI was increased (9.35plusmn;1.37AU/mi) comparing with those patients suffering from nonischemic retinopathy (the activities of t-PA and PAI were 1.92 + 0.53IU/ml and 8.42plusmn;1.29AU/ml respectively, Plt;0.01). In addition, these changes were getting more obvious with the degree of severity of the disease. These results indicated that there was disorder in the balance between t-PA and PAI in patients with RVO,which my play an important role in the course of occurrence and development of RVO, especially in ischemic type. （Chin J Ocul Fundus Dis,1994,10:71-73）